Characterization of Platinum Coated Electrodes Encapsulated in Microfluidic Channel for Impedancemetry Applications

The impedance properties of a fabricated electrode array coated by a platinum layer were investigated in a microfluidic channel. The platinum layers were electroplated on Au planar electrodes using a hexachloroplatinic acid (H
2
PTCl
6
) to increase the surface roughness, and hence decrease the impedance of the electrodes. To examine the adhesion of the coated platinum, the fabricated electrodes were sonicated in propanol solution. The microfluidic channel was fabricated using polydimethylsiloxane (PDMS), formed by a 3D printed mold. The impedance of the encapsulated electrodes in the microfluidic channel, injected by NaCl solution, was measured at 1 KHz frequency. In order to achieve the lowest possible impedance from the electrodes, the effect of the electroplating duration, the amplitude and the waveform of the applied plating current were studied. The electrode/electrolyte interface impedance was also analysed over the frequency range of 100Hz to 4 KHz, and the equivalent resistance and capacitance of the electrodes in contact with the ionic electrolyte were extracted.